Reclinable passenger seat

ABSTRACT

A reclinable passenger seat including a base, a seat pan frame having a front end connected to the base via a first fixed pivot, a support arm having one end connected to the base via a second fixed pivot aft of the first fixed pivot, and a backrest frame having an upper backrest member and a lower backrest member. An opposed end of the support arm is pivotally connected to the lower backrest member at a first location spaced from the upper backrest member. A rear end of the seat pan frame is pivotally connected to the lower backrest member at a second location between the first location and the upper backrest member. The backrest frame and seat pan frame are configured to move simultaneously between a sitting configuration and a reclined configuration through pivoting motion about the fixed pivots and about the two locations.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This International PCT Patent Application relies for priority on U.S.Provisional Patent Application Ser. No. 62/608,717 filed on Dec. 21,2017, the entire content of which is incorporated herein by reference.

TECHNICAL FIELD

The application relates generally to reclinable passenger seats and,more particularly, to such seats provided in aircraft.

BACKGROUND OF THE ART

A variety of different configurations exist for reclinable seats such asto allow the backrest and seat pan to move between sitting and reclinedconfigurations. Some of these existing configurations include slidemechanisms, for example provided between the base of the seat and thebackrest and/or seat pan, where rollers or other suitable slidingelements are received in straight or curved slots to guide the motion ofthe backrest and/or seat pan with respect to the base. However, slidemechanisms may be prone to misalignment and/or jamming.

SUMMARY

In one aspect, there is provided a reclinable passenger seat comprising:a base configured to be connected to a floor structure; a seat pan framesupporting a seat pan and having a front end connected to the base via afirst fixed pivot; a support arm having one end connected to the basevia a second fixed pivot located aft of the first fixed pivot; and abackrest frame having an upper backrest member supporting a backrest anda lower backrest member extending downwardly from the upper backrestmember, an opposed end of the support arm pivotally connected to thelower backrest member at a first location spaced from the upper backrestmember, a rear end of the seat pan frame pivotally connected to thelower backrest member at a second location between the first locationand the upper backrest member; wherein the backrest frame and seat panframe are configured to move simultaneously between a sittingconfiguration and a reclined configuration through pivoting motion aboutthe first and second fixed pivots and about the first and secondlocations.

In particular embodiments, the reclinable passenger seat may include anyone or any suitable combination of the following:

-   -   the upper and lower backrest members are interconnected by a        selectively lockable pivot connection having a locked        configuration where a relative pivoting motion between the upper        and lower backrest members is prevented and an unlocked        configuration where the relative pivoting motion between the        upper and lower backrest members is allowed;    -   the second fixed pivot connecting the support arm to the base is        located under the backrest frame;    -   the first and second locations on the lower backrest member        remain forward of the second fixed pivot as the backrest frame        and seat pan frame move between the sitting configuration and        the reclined configuration;    -   a gas spring having one end pivotally connected to the lower        backrest member and to the rear end of the seat pan frame at the        first location, and an opposed end pivotally connected to the        base by a third fixed pivot located between the first and second        fixed pivots;    -   the first and second locations on the lower backrest member        remain aft of the third fixed pivot as the backrest frame and        seat pan frame move between the sitting configuration and the        reclined configuration;    -   a distance between the second fixed pivot and the first location        is about twice a distance between the first and second        locations;    -   the upper and lower backrest members extend non-parallel to one        another;    -   the upper and lower backrest members extend at an angle of about        135 degrees with respect to one another.

In another aspect, there is provided a reclinable passenger seatcomprising: a base configured to be connected to a floor structure; aseat pan frame supporting a seat pan and having a front end connected tothe base via a first revolute joint; a support arm having one endconnected to the base via a second revolute joint located aft of thefirst revolute joint; and a backrest frame having an upper backrestmember supporting a backrest and a lower backrest member extendingdownwardly from the upper backrest member, the upper and lower backrestmembers having at least a first configuration where the upper and lowerbackrest members have a fixed orientation with respect to one another,an opposed end of the support arm connected to the lower backrest membervia a third revolute joint spaced from the upper backrest member, a rearend of the seat pan frame connected to the lower backrest member by afourth revolute joint located between the third revolute joint and theupper backrest member; wherein the backrest frame and seat pan frame areconfigured to move simultaneously between a sitting configuration and areclined configuration through pivoting motion about the first, second,third and fourth revolute joints while the upper and lower backrestmembers are in the first configuration.

In particular embodiments, the reclinable passenger seat may include anyone or any suitable combination of the following:

-   -   the upper and lower backrest members are interconnected by a        selectively lockable revolute joint, the first configuration        being a locked configuration where a relative pivoting motion        between the upper and lower backrest members is prevented, the        selectively lockable revolute joint having an unlocked        configuration where the relative pivoting motion between the        upper and lower backrest members is allowed;    -   the second revolute joint connecting the support arm to the base        is located under the backrest frame;    -   the third and fourth revolute joints on the lower backrest        member remain forward of the second revolute joint connecting        the support arm to the base as the backrest frame and seat pan        frame move between the sitting configuration and the reclined        configuration;    -   a gas spring having one end connected to the fourth revolute        joint connecting the seat pan frame to the lower backrest        member, and an opposed end pivotally connected to the base by a        fifth revolute joint located between the first and second        revolute joints;    -   the third and fourth revolute joints on the lower backrest        member remain aft of the fifth revolute joint connecting the gas        spring to the base as the backrest frame and seat pan frame move        between the sitting configuration and the reclined        configuration;    -   a distance between the second and third revolute joints is about        twice a distance between the third and fourth revolute joints;    -   in the first configuration, the upper and lower backrest members        extend non-parallel to one another;    -   in the first configuration, the upper and lower backrest members        extend at an angle of about 135 degrees with respect to one        another.

In a further aspect, there is provided a method of inclining areclinable seat, the method comprising: changing an angle of a seat panand an angle of a backrest of the seat by simultaneously: pivoting afront end of the seat pan about a first fixed location on a base of theseat; pivoting a support arm about a second fixed location on a base ofthe seat, the second fixed location being aft of the first fixedlocation; pivoting the backrest relative to the support arm about athird location on a lower backrest member of the backrest; and pivotingthe backrest relative to a rear end of the seat pan about a fourthlocation on the lower backrest member.

In particular embodiments, the method may include any one or anysuitable combination of the following:

-   -   a variation in the angle of the backrest has a linear        relationship with respect to a variation in the angle of the        seat pan;    -   the method further comprises applying a resistance against a        movement of the rear end of the seat pan;    -   the lower backrest member remains over the support arm as the        backrest pivots relative to the rear end and relative to the        support arm.

DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, as well as otheraspects and further features thereof, reference is made to the followingdescription which is to be used in conjunction with the accompanyingdrawings, where:

FIG. 1 is a schematic tridimensional view of an aircraft;

FIG. 2 is a schematic diagram of the structure of a seat which can beused in an aircraft such as shown in FIG. 1, in accordance with aparticular embodiment;

FIG. 3 is a schematic side view of the seat of FIG. 2 shown in sittingand reclined configurations, in accordance with a particular embodiment;

FIG. 4 is a schematic rear tridimensional view of part of the seat ofFIGS. 2-3, in accordance with a particular embodiment;

FIG. 5 is a diagram of an angle variation of the seat pan in relation toan angle variation of the backrest of the seat of FIGS. 2-4 uponmovement between the sitting and reclined configurations, in accordancewith a particular embodiment;

FIG. 6 is a diagram of the resultant force created by two gas springs,used alone and in combination, in the seat of FIGS. 2-4 as a function ofthe seat pan angle upon movement between the sitting and reclinedconfigurations, in accordance with particular embodiments;

FIG. 7a is a schematic side view of the seat of FIGS. 2-4 in the sittingconfiguration, in accordance with a particular embodiment;

FIG. 7b in a schematic side view of the seat of FIG. 7a in an uprightconfiguration;

FIG. 7c is a schematic side view of the seat of FIG. 7a in a berthconfiguration;

FIG. 8a is a schematic side view of a seat in accordance with anotherembodiment, in the sitting configuration;

FIG. 8b in a schematic side view of the seat of FIG. 8a in the reclinedconfiguration; and

FIG. 8c is a schematic side view of the seat of FIG. 8a in the berthconfiguration.

DETAILED DESCRIPTION

Referring to the drawings and more particularly to FIG. 1, an aircraftis shown at 1 and is generally described to illustrate some componentsfor reference purposes in the present disclosure. The aircraft 1 has afuselage 2 having a fore end at which a cockpit is located, and an aftend supporting a tail assembly, with the cabin generally located betweenthe cockpit and the tail assembly. The tail assembly comprises avertical stabilizer 3 with a rudder, and horizontal stabilizers 4 withelevators. The tail assembly has a fuselage-mounted tail, but otherconfigurations may also be used for the aircraft 1, such as cruciform,T-tail, etc. Wings 5 project laterally from the fuselage. The aircraft 1has engines 6 supported by the wings 5, although the engines 6 couldalso be mounted to the fuselage 2. The aircraft 1 is shown as ajet-engine aircraft, but may also be a propeller aircraft. It is alsounderstood that although FIG. 1 shows a commercial aircraft, theaircraft 1 may alternately be any other type of aircraft, including, butnot limited to, a business aircraft or a private aircraft.

Referring to FIGS. 2-5, a passenger seat 10 in accordance with aparticular embodiment is shown. The passenger seat 10 is configured tobe used, for example, in the cabin of an aircraft 1 such as shown inFIG. 1. The passenger seat 10 could alternately be used in any othersuitable type of vehicle.

Referring particularly to FIG. 2, the seat 10 includes a base or carrier12 which is configured to be connected to a floor structure 7, forexample to floor beams interconnected to the fuselage 2. In theembodiment shown, the base 12 is connected to a pivot 8 which isslidingly received on rails 9 attached to the floor structure 7,allowing the base 12 to be displaced along a limited path defined by therails 9 and pivoted about the pivot 8; the pivot 8 is located toward therear of the base 12, such that a greater part of the base 12 is locatedin front if the pivot 8. It is however understood that the attachmentbetween the base 12 and floor structure 7 shown here is exemplary onlyand that any other suitable type of attachment may alternately be used,including, but not limited to, pivoting attachments, slidingattachments, and fixed attachments.

Referring particularly to FIG. 3, the seat 10 generally includes a seatpan frame 14 supporting a seat pan 15, and a backrest frame 16supporting a backrest 17. It is understood that the seat pan 15 andbackrest 17 may include any material suitable for providing appropriatesupport and comfort to the occupant, including, but not limited to,suitable cushioning materials which will not be further describedherein. The seat 10 is selectively configurable between a sittingconfiguration S shown in full lines and a reclined configuration R shownin dotted lines. In a particular embodiment, the sitting configuration Scorresponds to a taxi, take-off and landing (TTOL) configuration.

Referring to FIGS. 2-4, the backrest frame 16 has an upper backrestmember 16 a supporting the backrest 17, and a lower backrest member 16 bextending downwardly from a bottom end of the upper backrest member 16a. In the embodiment shown, the upper and lower backrest members 16 a,16 b are pivotally interconnected by a selectively lockable pivotconnection 18, e.g. a selectively lockable revolute joint. In thepresent disclosure, including claims, the term “revolute joint” isintended to designate a pivot connection between two members whichallows relative pivoting motion between the two members about an axis ofrotation without allowing relative translation between the two members,i.e. the axis of rotation has a fixed location with respect to each ofthe two members. Examples of revolute joints include, but are notlimited to, a hinge joint, a pin joint, and a folding joint.

The pivot connection 18 between the upper and lower backrest members 16a, 16 b has a locked configuration where a relative pivoting motionbetween the upper and lower backrest members 16 a, 16 b is prevented andan unlocked configuration where the relative pivoting motion between theupper and lower backrest members 16 a, 16 b is allowed. The pivotconnection 18 may include, for example, a lock based on a spring-loadedplunger mechanism; any other suitable mechanism may alternately be used.As will be detailed further below, in a particular embodiment the upperand lower backrest members 16 a, 16 b remain with a fixed relativeorientation with respect to one another (i.e. the pivot connection 18between the upper and lower backrest members 16 a, 16 b remains in thelocked configuration) as the seat 10 is moved from the sittingconfiguration S to the reclined configuration R, and from the reclinedconfiguration R to the sitting configuration S; the pivot connection isonly unlocked when the seat 10 is moved to a berth configuration B (FIG.7c ). In the embodiment shown, the upper and lower backrest members 16a, 16 b are non-parallel when in the locked configuration. It isunderstood that in an alternate embodiment, the upper and lower backrestmembers 16 a, 16 b may be rigidly interconnected.

Referring particularly to FIG. 2, in the embodiment shown, the backrest17 also includes a headrest 20 which is slidingly engaged to a top ofthe upper backrest member 16 a. The headrest 20 may include a pivotableportion 20 a allowing for further adjustment of the position of theheadrest 20. It is understood that the headrest configuration shown isexemplary only, and that any other suitable headrest configuration mayalternately be used; alternately, the adjustable headrest may beomitted.

The front end of the seat pan frame 14 is connected to the front of thebase 12 via a pivot connection 22, which in the embodiment shown isdefined by a revolute joint or fixed pivot, i.e. a pivot having a fixedlocation on the base 12. Referring particularly to FIG. 4, in aparticular embodiment, the base 12 includes two laterally spacedinterconnected portions 12 a; the front end of the seat pan frame 14 isreceived between the front ends of the base portions 12 a and ispivotally connected thereto. The pivot connection 22 may be defined by asingle pivot interconnecting the front end of the seat pan frame 14 toboth base portions 12 a, or by separate pivots interconnecting the frontend of the seat pan frame 14 to each base portion 12 a. Otherconfigurations are also possible.

Referring back to FIGS. 2-4, the backrest frame 16 is connected to thebase 12 by a support arm 24 and is free of direct connections with thebase 12. The support arm 24 has one end connected to the base 12 viaanother pivot connection 26, which in the embodiment shown is alsodefined as a fixed pivot or revolute joint. The pivot connection 26between the support arm 24 and the base 12 is located aft of the pivotconnection 22 between the front end of the seat pan frame 14 and thebase 12 and, in the embodiment shown, is located at the rear of the base12. The pivot connection 22 between the front end of the seat pan frame14 and the base 12 is upwardly offset with respect to the pivotconnection 26 between the support arm 24 and the base 12.

The support arm 24 has an opposed end pivotally connected to the lowerbackrest member 16 b by another pivot connection 28 defined at alocation spaced from the upper backrest member 16 a. In the embodimentshown, the pivot connection 28 between the support arm 24 and the lowerbackrest member 16 b is defined by another revolute joint.

Referring particularly to FIG. 4, in a particular embodiment, thesupport arm 24 includes two laterally spaced interconnected rods 24 a,and the lower backrest member 16 b includes two laterally spacedinterconnected portions 16 b′. The pivot connection 28 between thesupport arm 24 and the lower backrest member 16 b is defined by separatepivots interconnecting the end of each of the lower backrest memberportions 16 b′ to the end of a respective one of the rods 24 a, and thepivot connection between the support arm 24 and the base 12 is definedby separate pivots interconnecting the other end of each of the rods 24a to the base 12. Other configurations are also possible.

Referring back to FIGS. 2-4, the backrest frame 16 and seat pan frame 14are also interconnected: the rear end of the seat pan frame 14 ispivotally connected to the lower backrest member 16 b by another pivotconnection 30 defined at a location between the upper backrest member 16a and the pivot connection 28 between the support arm 24 and the lowerbackrest member 16 b. In the embodiment shown, the pivot connectionbetween the lower backrest member 16 b and the rear end of the seat panframe 14 is defined by another revolute joint. Referring particularly toFIG. 4, in a particular embodiment, the pivot connection 30 between thelower backrest member 16 b and the seat pan frame 14 is defined by asingle pivot interconnecting both lower backrest member portions 16′ tothe rear end of the seat pan frame 14. Other configurations are alsopossible.

Referring to FIG. 3, the backrest frame 16 and seat pan frame 14 movesimultaneously between the sitting configuration S and the reclinedconfiguration R through pivoting motion about the four pivot connections22, 26, 28, 30 defined between the seat pan frame 14 and the base 12,between the support arm 24 and the base 12, between the support arm 24and the lower backrest member 16 b, and between the lower backrestmember 16 b and the seat pan frame 14, while the upper and lowerbackrest members 16 a, 16 b remain at a fixed orientation with respectto one another, e.g. while the pivot connection 18 between the upper andlower backrest members 16 a, 16 b remains in the locked configuration.

It can be seen that the pivot connection 26 between the support arm 24and the base 12 is located under the backrest frame 16, and the backrestframe 16 remains over this pivot connection 26 throughout the motion ofbackrest frame 16 and seat pan frame 14 between the sitting and reclinedconfigurations S, R. The support arm 24 also remains under the backrestframe 16, and the two pivot connections 28, 30 of the lower backrestmember 16 b remain forward of and higher than the pivot connection 26between the support arm 24 and the base 12 throughout this motion.

Referring to FIG. 2, in a particular embodiment, the effective length d₁of the support arm 24 defined by the distance between the two pivotconnections 26, 28 of the support arm 24, the effective length d₂ of thelower backrest member 16 b defined by the distance between the two pivotconnections 28, 30 of the lower backrest member 16 b, and the angle αbetween the upper and lower backrest members 16 a, 16 b when in thelocked configuration are selected so that the variation in the angle ofthe backrest 17 has a linear relationship with respect to a variation inthe angle of the seat pan 15 as the seat pan frame 14 and backrest frame16 are moved between the sitting and reclined configurations S, R.

FIG. 5 shows examples of the angle variation of the seat pan in relationto the angle variation of the backrest for different seatconfigurations, with lines M showing maximum targeted variations. CurveA shows a theoretical linear relationship, while curves B and C showrelationships which are sufficiently close to the theoretical linearrelationship A to be characterized as linear. In a particularembodiment, curve B corresponds to the seat 10 of FIGS. 2-4 where theeffective length d₁ of the support arm 24 is twice or about twice theeffective length d₂ of the lower backrest member 16 b, and where theupper and lower backrest members 16 a, 16 b extend at an angle α of 135degrees or about 135 degrees to each other in the locked configuration.In another embodiment, the effective length d₁ of the support arm 24 isabout 1.875 times the effective length d₂ of the lower backrest member16 b with the angle α being 135 degrees or about 135 degrees. In aparticular embodiment, the effective length d₂ of the lower backrestmember 16 b is about ¼ the length of the seat pan frame 14 as measuredbetween its pivot connections 22, 30, and the effective length d₁ of thesupport arm 24 is from 1.875 to 2 times the effective length d₂ of thelower backrest member 16 b with the angle α being 135 degrees or about135 degrees. In a particular embodiment, all these combinations ofvalues are applicable for a seat pan depth of 16 inches, and a reclineangle range of 5 to 15 degrees for the seat pan and 20 to 43 degrees forthe backrest. Other values are also possible. By contrast, curve D showsa relationship which is not linear; in a particular embodiment, thiscorresponds to a seat where the upper and lower backrest members 16 a,16 b are parallel or approximately parallel, and where the effectivelength d₁ of the support arm 24 is more than twice the effective lengthd₂ of the lower backrest member 16 b. In a particular embodiment, thelinear relationship between the variation in the angle of the seat pan15 and the variation in the angle of the backrest 17 provides for a morestable motion between the sitting and reclined configurations S, R,which may be easier to operate and/or more comfortable for the occupant,then a seat where the relationship is not linear.

Referring back to FIG. 2, the seat 10 further includes a biasing and/ordamping member, for example a gas spring 32 or any suitable type oflinear actuator located under the seat pan frame 14. In a particularembodiment, having the gas spring 32 located under the seat pan frame 14as opposed to in behind the backrest frame 16 allows for the backrest 17to have a reduced thickness, which may provide increased free space forthe occupant(s) of the adjacent seat(s).

In the embodiment shown, the gas spring 32 has one end pivotallyconnected to the lower backrest member 16 b and to the rear end of theseat pan frame 14 at the pivot connection 30 between the lower backrestmember 16 b and the rear end of the seat pan frame 14. For example andreferring to FIG. 4, the lower backrest member 16 b and the rear end ofthe seat pan frame 14 may be interconnected by a revolute joint definedby a rod 34, with the lower backrest member portions 16 b′ and the rearend of the seat pan frame 14 pivotally engaged to the rod 34 adjacentits ends, and the end of the gas spring 32 pivotally engaged to acentral portion of the rod 34. Other configurations are of coursepossible.

Referring back to FIG. 2, the opposed end of the gas spring 32 ispivotally connected to the base 12 by a pivot connection 36, which inthe embodiment shown is also defined as a fixed pivot or revolute joint.The pivot connection 36 between the gas spring 32 and the base 12 islocated between the pivot connections 22, 26 of the base 12 with thefront end of the seat pan frame 14 and with the support arm 24.

In a particular embodiment, the gas spring 32 is positioned so that themovement of its end connected to the lower backrest member 16 b and tothe seat pan frame 14 is as close as possible to the axis of the gasspring 32 so as to maximize the efficiency of the gas spring 32. In aparticular embodiment, the gas spring 32 is selected so that its strokeduring the motion of the seat pan frame 14 and backrest frame 16 is atmost ⅓ of the total extended length of the gas spring 32; other valuesare also possible.

In the embodiment shown, the gas spring 32 is connected toward the frontof the base 12, so that its connection with the base 12 remains forwardof its connection with the lower backrest member 16 b and seat pan frame14 throughout the motion of backrest frame 16 and seat pan frame 14between the sitting and reclined configurations S, R. It can be seenfrom FIG. 3 that the pivot connections 28, 30 of the lower backrestmember 16 b remain aft of the pivot connection 36 between the gas spring32 and the base 12 as the backrest frame 16 and seat pan frame 14 movebetween the sitting configuration S and the reclined configuration R.

Referring to FIG. 6, in a particular embodiment the attachment of thegas spring 32 toward the front of the base 12 and forwardly of thebackrest frame 16 allows for the resultant force on the backrest andnormal to the backrest (i.e. the resultant force pushing on the occupantback) for a constant force applied by the gas spring 32 to increase nearthe reclined configuration R, such as shown for example by curve E. Bycontrast, curve F corresponds to a gas spring 32′ attached toward therear of the base 12, for example between the pivot connection betweenthe lower backrest member 16 b and the seat pan frame 14 and the pivotconnection 26 between the support arm 24 and the base 12 (see dottedlines in FIG. 2); it can be seen that the resultant force is decreasingfrom the sitting configuration S to the reclined configuration R. CurveG shows the resultant force when the two gas springs 32, 32′ areprovided, one attached toward the front of the base 12 and anothertoward the rear; it can be seen that in this configuration, theresultant force also decreases at the reclined configuration R. In aparticular embodiment, having the resultant force increasing toward thereclined configuration as per curve E provides for a more comfortabletransition from the sitting configuration S to the reclinedconfiguration R for the occupant.

Referring to FIG. 7b , in a particular embodiment the seat 10 also hasan upright configuration U, where the backrest 17 is closer to thevertical (more upright) than in the sitting configuration S (FIG. 7a )and/or where the seat pan frame 14 is horizontal or approximatelyhorizontal. The seat pan frame 14 and backrest frame 16 movesimultaneously between the sitting configuration S (FIG. 7a ) and theupright configuration U (FIG. 7b ) through pivoting motion about thefour pivot connections 22, 26, 28, 30 defined between the seat pan frame14 and the base 12, between the support arm 24 and the base 12, betweenthe support arm 24 and the lower backrest member 16 b, and between thelower backrest member 16 b and the seat pan frame 14, while the upperand lower backrest members 16 a, 16 b remain at a fixed orientation withrespect to one another, e.g. while the pivot connection 18 between theupper and lower backrest members 16 a, 16 b remains in the lockedconfiguration.

Referring to FIG. 7c , in a particular embodiment the seat 10 also has aberth configuration B, where the backrest 17 and seat pan 15 are alignedor approximately aligned, for example so that the seat 10 may serve as abed. In the embodiment shown, the seat 10 is configured between theupright configuration U and the berth configuration B by unlocking thepivot connection 18 between the upper and lower backrest members 16 a,16 b, and pivoting the upper backrest member 16 a rearwardly withrespect to the lower backrest member 16 b about the unlocked pivotconnection 18. The position of the support arm 24, seat pan frame 14 andlower backrest member 16 b is the same between the upright configurationU (FIG. 7b ) and the berth configuration B (FIG. 7c ), i.e. the seat 10is configured between the upright configuration U and the berthconfiguration B without any pivoting motion about the four pivotconnections 22, 26, 28, 30 defined between the seat pan frame 14 and thebase 12, between the support arm 24 and the base 12, between the supportarm 24 and the lower backrest member 16 b, and between the lowerbackrest member 16 b and the seat pan frame 14.

Referring to FIGS. 8a, 8b and 8c , a seat 110 in accordance with anotherembodiment is shown, where elements similar to the correspondingelements of the seat 10 of FIGS. 2-4 are identified by the samereference numerals and will not be further described herein. In thisembodiment, the upper and lower backrest members 116 a, 116 b have afixed orientation with respect to one another (i.e. are rigidlyinterconnected), and are parallel or approximately parallel to eachother. The pivot connection 126 between the support arm 124 and the base12 is forwardly offset with respect to the corresponding pivotconnection 26 of the seat of FIGS. 2-4: the pivot connection 126 betweenthe support arm 124 and the base 12 remains in front of the two pivotconnections 28, 30 of the lower backrest member 116 b and in front ofthe backrest frame 116 throughout the motion of the backrest frame 116and seat pan frame 14 between the sitting configuration S (FIG. 8a ),reclined configuration R (FIG. 8b ), and berth configuration B (FIG. 8c). The pivot connection 126 between the support arm 124 and the base 12is lower than the lower backrest member 116 b in the sittingconfiguration S and in the berth configuration B, but is higher than thelower backrest member 116 b in the reclined configuration R.

In a particular embodiment, this configuration allows for the seat 10 tobe configured from the sitting configuration S (FIG. 8a ) to thereclined configuration R (FIG. 8b ) and from the sitting configuration Sor reclined configuration R to the berth configuration B (FIG. 8c )through pivoting motion about the four pivot connections 22, 126, 28, 30defined between the seat pan frame 14 and the base 12, between thesupport arm 124 and the base 12, between the support arm 124 and thelower backrest member 116 b, and between the lower backrest member 116 band the seat pan frame 14, without the need for relative motion betweenthe upper and lower backrest member 116 a, 116 b. However, in aparticular embodiment, the attachment of the support arm 124 toward thefront and the support arm 124 located forwardly of the backrest frame116 may provide for a seat motion which may be less stable and/or morecomplex than that of the seat 10 of FIGS. 2-4

In a particular embodiment and in use, reclining the seat 10, 110includes changing the angle of the seat pan 15 and the angle of thebackrest 17 by simultaneously pivoting the front end of the seat pan 15about a first fixed location defined by the pivot connection 22 betweenthe seat pan frame 14 and the base 12, pivoting the support arm 24, 124about a second fixed location defined by the pivot connection 26, 126between the support arm 24, 124 and the base 12 and which is located aftof the first fixed location 22, pivoting the backrest 17 relative to thesupport arm 24, 124 about a third location defined by the pivotconnection 28 between the support arm 24, 124 and the lower backrestmember 16 b, 116 b, and pivoting the backrest 17 relative to the rearend of the seat pan 15 about a fourth location defined by the pivotconnection 30 between the seat pan frame 14 and the lower backrestmember 16 b, 116 b.

In a particular embodiment, reclining the seat 10, 110 includes applyinga resistance against the movement of the rear end of the seat pan 15,for example with the gas spring 32, 32′.

In a particular embodiment, the configuration of the pivot connections22, 26, 126, 28, 30 allows for the motion of the seat 10, 110 to beeasier and/or more comfortable when compared to a similar seat havingone or more sliding mechanism(s) involved in the motion of the seat. Ina particular embodiment, the configuration of the pivot connections 22,26, 126, 28, 30 allows for a range of motion for the seat 10, 110similar to that of a seat having one or more sliding mechanism(s).

While the methods and systems described herein have been described andshown with reference to particular steps performed in a particularorder, it will be understood that these steps may be combined,sub-divided or reordered to form an equivalent method without departingfrom the teachings of the present invention. Accordingly, the order andgrouping of the steps is not a limitation of the present invention.

Modifications and improvements to the above-described embodiments of thepresent invention may become apparent to those skilled in the art. Theforegoing description is intended to be exemplary rather than limiting.The scope of the present invention is therefore intended to be limitedsolely by the scope of the appended claims.

1. A reclinable passenger seat comprising: a base configured to beconnected to a floor structure; a seat pan frame supporting a seat panand having a front end connected to the base via a first fixed pivot; asupport arm having one end connected to the base via a second fixedpivot located aft of the first fixed pivot; and a backrest frame havingan upper backrest member supporting a backrest and a lower backrestmember extending downwardly from the upper backrest member, an opposedend of the support arm pivotally connected to the lower backrest memberat a first location spaced from the upper backrest member, a rear end ofthe seat pan frame pivotally connected to the lower backrest member at asecond location between the first location and the upper backrestmember; wherein the backrest frame and seat pan frame are configured tomove simultaneously between a sitting configuration and a reclinedconfiguration through pivoting motion about the first and second fixedpivots and about the first and second locations.
 2. The reclinablepassenger seat as defined in claim 1, wherein the upper and lowerbackrest members are interconnected by a selectively lockable pivotconnection having a locked configuration where a relative pivotingmotion between the upper and lower backrest members is prevented and anunlocked configuration where the relative pivoting motion between theupper and lower backrest members is allowed.
 3. The reclinable passengerseat as defined in claim 1, wherein the second fixed pivot connectingthe support arm to the base is located under the backrest frame.
 4. Thereclinable passenger seat as defined in claim 3, wherein the first andsecond locations on the lower backrest member remain forward of thesecond fixed pivot as the backrest frame and seat pan frame move betweenthe sitting configuration and the reclined configuration.
 5. Thereclinable passenger seat as defined in claim 1, further comprising agas spring having one end pivotally connected to the lower backrestmember and to the rear end of the seat pan frame at the first location,and an opposed end pivotally connected to the base by a third fixedpivot located between the first and second fixed pivots.
 6. Thereclinable passenger seat as defined in claim 5, wherein the first andsecond locations on the lower backrest member remain aft of the thirdfixed pivot as the backrest frame and seat pan frame move between thesitting configuration and the reclined configuration.
 7. The reclinablepassenger seat as defined in claim 1, wherein a distance between thesecond fixed pivot and the first location is about twice a distancebetween the first and second locations.
 8. The reclinable passenger seatas defined in claim 1, wherein the upper and lower backrest membersextend non-parallel to one another.
 9. The reclinable passenger seat asdefined in claim 8, wherein the upper and lower backrest members extendat an angle of about 135 degrees with respect to one another.
 10. Areclinable passenger seat comprising: a base configured to be connectedto a floor structure; a seat pan frame supporting a seat pan and havinga front end connected to the base via a first revolute joint; a supportarm having one end connected to the base via a second revolute jointlocated aft of the first revolute joint; and a backrest frame having anupper backrest member supporting a backrest and a lower backrest memberextending downwardly from the upper backrest member, the upper and lowerbackrest members having at least a first configuration where the upperand lower backrest members have a fixed orientation with respect to oneanother, an opposed end of the support arm connected to the lowerbackrest member via a third revolute joint spaced from the upperbackrest member, a rear end of the seat pan frame connected to the lowerbackrest member by a fourth revolute joint located between the thirdrevolute joint and the upper backrest member; wherein the backrest frameand seat pan frame are configured to move simultaneously between asitting configuration and a reclined configuration through pivotingmotion about the first, second, third and fourth revolute joints whilethe upper and lower backrest members are in the first configuration. 11.The reclinable passenger seat as defined in claim 10, wherein the upperand lower backrest members are interconnected by a selectively lockablerevolute joint, the first configuration being a locked configurationwhere a relative pivoting motion between the upper and lower backrestmembers is prevented, the selectively lockable revolute joint having anunlocked configuration where the relative pivoting motion between theupper and lower backrest members is allowed.
 12. The reclinablepassenger seat as defined in claim 10, wherein the second revolute jointconnecting the support arm to the base is located under the backrestframe.
 13. The reclinable passenger seat as defined in claim 12, whereinthe third and fourth revolute joints on the lower backrest member remainforward of the second revolute joint connecting the support arm to thebase as the backrest frame and seat pan frame move between the sittingconfiguration and the reclined configuration.
 14. The reclinablepassenger seat as defined in claim 10, further comprising a gas springhaving one end connected to the fourth revolute joint connecting theseat pan frame to the lower backrest member, and an opposed endpivotally connected to the base by a fifth revolute joint locatedbetween the first and second revolute joints.
 15. The reclinablepassenger seat as defined in claim 14, wherein the third and fourthrevolute joints on the lower backrest member remain aft of the fifthrevolute joint connecting the gas spring to the base as the backrestframe and seat pan frame move between the sitting configuration and thereclined configuration.
 16. The reclinable passenger seat as defined inclaim 10, wherein a distance between the second and third revolutejoints is about twice a distance between the third and fourth revolutejoints.
 17. The reclinable passenger seat as defined in claim 10,wherein in the first configuration, the upper and lower backrest membersextend non-parallel to one another.
 18. The reclinable passenger seat asdefined in claim 17, wherein in the first configuration, the upper andlower backrest members extend at an angle of about 135 degrees withrespect to one another.
 19. A method of inclining a reclinable seat, themethod comprising: changing an angle of a seat pan and an angle of abackrest of the seat by simultaneously: pivoting a front end of the seatpan about a first fixed location on a base of the seat; pivoting asupport arm about a second fixed location on a base of the seat, thesecond fixed location being aft of the first fixed location; pivotingthe backrest relative to the support arm about a third location on alower backrest member of the backrest; and pivoting the backrestrelative to a rear end of the seat pan about a fourth location on thelower backrest member.
 20. The method as defined in claim 19, wherein avariation in the angle of the backrest has a linear relationship withrespect to a variation in the angle of the seat pan.
 21. The method asdefined in claim 19, further comprising applying a resistance against amovement of the rear end of the seat pan.
 22. The method as defined inclaim 19, wherein the lower backrest member remains over the support armas the backrest pivots relative to the rear end and relative to thesupport arm.